Using vitamin C products beyond the recommended limits can cause stomach aches and diarrhea. Even though the body would only use the vitamin it needs, an overdose of vitamin C can hinder metabolic activities in the body.
The recommended daily allowance (RDA) for vitamin C in non-smoking adults is 75 mg a day for women and 90 mg a day for men. For smokers, the recommended daily doses are 110 mg per day for women and 125 mg per day for men. A dose of 200 milligrams daily is almost sufficient to maximize plasma and lymphocyte levels.
Higher levels of vitamin C are needed when you are under environmental stress such as trauma, fever, or infection. Full saturation is achieved with daily intakes of 200-500 mg per day (in 2-3 divided doses). This is a water soluble protein and the body excretes any excess. Vitamin C overdose can cause diarrhea, gas, or an upset stomach. Other side effects could be stomach cramps, nausea and diarrhea, and an increased risk of developing kidney stones. Large amounts of vitamin C reduce the body’s levels of copper, an essential nutrient. People with iron overload diseases should avoid overdosing on vitamin C, as it increases iron absorption. People who have kidney stones should follow special medical advice. If a pregnant mother takes 6000 mg of vitamin C, the baby can develop rebound scurvy due to a sudden drop in daily intake. Hemochromatosis patients should not take vitamin C due to the increased accumulation of non-heme iron in the presence of this vitamin.